Engine



- May 14, 192 9. R. A. FORBES 1, 13,491

ENGINE Filed Sept. 21, 1925 '2 Sheets-Sheet l y 14, 9 R. A. FORBES 1,713,491

ENGINE Filed Sept. 21. 1925 2 Sheets-Sheet 2 Patented May 14, 1929.

UNITED STATES 7 ROBERT A. FORBES, 0F HAMILTON, OHIO, ASSIGNOB OF ONE-FIFTH T0 ARTHUR F.

nunnaa, or HAMILTON, 01110.

ENGINE.

Application filed September 21, 1925-. Serial No. 57,657. i

within the engine cylinder due to the movement of the engine piston. Another object is to provide an engine with auxiliary means for operating certain valves from the valve gear of other valves.

Still another object of the invention is to so reduce resistance to engine cranking as to enable the engine to be cranked by a small dynamo electric machine having a permanent driving connection with the engine and adapted to operate as a generator after the engine has become self-operative. I

A further object is to provide as an attachment or an accessory for a self-contained engine, means for reducing the resistance to engine cranking resulting from compression and expansion of the gas in the engine cylinder.

The present invention is shown, for convenience in illustration, as associated with a four cylinder, four-stroke-cycle internal combustion engine of a well known make, but it will be understood that the invention may be readily applied to other forms of engines.

Referring to the drawing Fig. 1 is a fragmentary plan view somewhat diagrammatic in form, of a motor vehicle having the present invention embodied therein;

Fig. 2 is a fragmentary side elevation of the engine illustrated in Fig. 1 showing the presentinvention associated therewith:

Figs. 3, t, and 5, are enlarged vertical sectional views taken on the lines 3-3, 44, and 55 of Fig. 2;

Fig. 6 is a section on the line 66 of Fig. 5;

Fig. 7 is a fragmentary sectional view on the line 7 7 of Fig. 2, parts being omitted for clearness in illustration;

Fig. 8 is an enlarged detail taken on the line 88 of Fig. 1, and

Fig. 9 is a section taken on the line 9 of Fig. 2. v

Referring particularly to Fig. 1 of the drawing, represents the chassis of a motor vehicle having mounted thereon an internal combustion engine 21 herein illustrated as a four cylinder water-cooled engine of the fourstroke-cycle type. As is well understood in the art, such an engine comprising generally a cylinder blockhaving cylinders bored there- 1n, plstons reciprocable in the cylinders, and a crankshaftconnected with the pistons by means of connecting rods, all of usual construct-ion and therefore not illustrated herein. The engine 21 is provided at the front end of the crankshaft with the usual hand crank 22 for cranking the engine. The engine is also provided with a starting, lighting and lgmtion system, and engine cranking may be accomplished electrically by pressing a starting switch button 25, which is accessible from the drivers seat, and which when de ressed closes a circuit from the battery 26 t rough the dynamo electric machine 27 to operate the latter as a motor. The dynamo electric machine is connected with the engine crankshaft through a suitable chain drive 28, gears, or other driving connection, the ratio of speed between the armature of the dynamo electric machine 27 and the. crankshaft of engine 21 being preferably the same whether the dynamo electric machine 27 is operable as a motor or as a generator. The electrical system may be provided with a voltage coil 29 having an armature 30 which is attracted when the dynamo voltage rises to a predetermined value, thereby connecting the battery 26 with the dynamo electric machine 27, to be charged thereby.

Internal combustion engines of the most approved form generally offer considerable resistance to'cranking, a large part of which is attributable to the load which results from the compression and the expansion of the gases in the cylinder by reason of the movements of the piston, and particularly to the irregularity of such load. The resistance to engine cranking resulting from this and other causes, particularly when the engine is new or is exposed to lowtemperatures, is often so great that many users of motor vehicles are compelled to go to the expense of pur-.

chasing electrical starting equipment, but even when such equipment is employed, the

high resistance to engine starting results in excessive demand upon the battery and consequently early depletion thereof.

The present invention contemplates the provision of an attachment or accessory for the elimination or reduction of resistance to engine cranking resulting from expansion and compression of gases in the engine cylinder, thereby greatly facilitating the engine cranking operation.

Referring particularly to Figs. 2 to 7 35,

36, 37, and 38 represent the exhaust valve stems of the four cylinder engine illustrated in Fig. 1, while 40, 41, 4:2, and 43 represent the stems of the intake valves. The valves are normally held to their seats by suitable valve springs, springs 45 being provided for the exhaust valves and springs at; for the intake valves. 'The engine is provided with the usual means for raising orunseating the valves, such means comprising push rods l'l the upper ends of which are adapted to abut the lower ends of the valve stems, and the lower ends of which ride upon and are adapted to be actuated by valve cams carried by the camshaft, the construction and arrang ment of such cams and camshafts being well known to those skilled-in the art and therefore not deemed necessary to be illustrated.

The usual arrangement in a four cylinder enall) ' gine, such as illustrated, is such that two of the pistons are on their up strokes at the same time, while the other two pistons are on their down strokes. In Fig. 2 the pistons for cylinders Nos. 1 and 4.- are assumed to be moving upwardly together while the pistons in cylinders Nos. 2 and 3 are moving downwardly together. If the piston in cylinder No. 1

is on its exhaust stroke then the piston in.

cylinder No. 4 is on its compression stroke, and likewise if the piston in cylinder No. 2 is on its intake stroke then the piston in cylinder No. 3 is on its firing stroke. The

arrangement of cams onthe camshaft is of course such as'to operate the intake and the exhaust valves in their proper sequence to upon the valve stem by a pin 51. Loosely mounted upon theexhaust valve stems are rings or collars 55, 56, 57 and 58 which are oined togetherm palrs, collars 55 and 56 being joined by red 59, and collars 57 and 58 being joined by rods 60. These collars surrounding the exhaust valve stems are interposed bctween the pins 51 and the push rods a7, and being smaller than the push rods 47,

they are raised by the latter simultaneously with the valve stems with which they are associated.

A frame or bracket 63 1S fixedly mounted in front of the several valve gears at a level threaded opening 65 in the cylinder block,-

which opening normally receives the screw threaded bolt by which a cover is secured over the valve i'nechanlsm. The screw threaded bolt, above referred to, is removed and replaced bythe stud (i l, the bracket 63 being rigidly held 111 place upon the stud 64 by means of suitable fastening devices 66. The

outer end of the studba is extended suliiciently to receive a cover (not shown) for enclosing the valve mechanism.

Bracket 63 is provided ad acent Il'S'CIIClS with upwardly extending lugs 68' which are provided with inwardly opening slots 69 adapted to serve as bearings for a rocker shaft 70 which extends lengthwise of the bracket 63 and lies between said bracket and the push rods 47, as best shown in Fig. l. The rocker shaft 70 carries transversely extending arms 71 having elongated slots 72 which are adapted to engage the rods 59 and 60 adjacent the exhaust valve stems'35 and 38 respectively. A short rocker shaft 75 is mounted upon the central portion of the long rocker shaft 70,'as shown in Figs. 3 and 7, and the short rocker shaft is provided with slotted arms 76 similar in construction and arrangement to the slotted arms 71 upon the long rocker shaft, the slotted arms 76 en; gaging the rods 59 and 60 adjacent to the exhaust valve stems 36 and 37 respectively.

The position of'the rocker shafts 70 and 75 during normal operation of the engine is shown in full lines in Figs. 3, 4t, and 7, and it will be noted that the slots which engage the rods 59 and 60 are substantially vertical so that risin and fallin movements of the rods 59 and 60' caused by corres 'ioi'iding movements of the exhaust valves, have no affect upon the rocker shafts 7 O and 7 5 since therods 59 and GO simply slide up and down in the slots formed in the arms 71 and 76.

To relieve compression during engin starting, rocker shaft 70 is moved into th bearing slot 69, as shown in dotted lines at 70 in Fig. 4, such movement of course carry- 'ing with it the rocker shaft 75. Rocker shaft arms 71 and 76 are now,substantial y horizontal and it will be apparent that any rising or falling movement of the exhaust valve adj acent one of the arms 71 will be transmitted through the long rocker shaft 70 and other arm 71.to the exhaust valve associated therewith. It has been assumed herein that.

cylinder No. 1 is transmitted through the rocker shaft 70 to the exhaust valve stem 38 fill compression stroke. The exhaust valve stem 38 of cylinder No. 4 is thus operated by the exhaust valve gear of cylinder No.1, thereby relieving the compression in cylinder No. 4. Similarly when exhaust valve stem 38 is elevated during the exhaust stroke of cylinder No. 4, such movement will be transmitted through rocker shaft 70 to exhaust valve stem to relieve compression in cylinder No. 1.

At the time of upward movement of the pistons in cylinders Nos. 1 and 4, the pistons in cylinders Nos. 2 and 3 are moving downwardly and the exhaust valves are inactive,

and as a consequence no movement is transmitted through the short rocker shaft 75. But when either of the pistons in cylinders Nos. 2 and 3 move upwardly on their exhaust strokes there is a lifting movement of the corresponding exhaust valve stem and such movement is transmitted by means of the short rocker shaft 75 and the rocker arms 76 to the other exhaust valve thereby relieving compression in the other cylinder.

Means is also provided for relieving the resistance to engine cranking resulting from the partial vacuum caused by expansion or rarefaction of the gas in the cylinders during the-down strokes of the pistons. Such means is preferably so associated with the rocker shaft 7 0 and arranged as to be rendered operative or inoperative by mdvement of the rocker shaft between its full line and dotted line positions, shown in Fig. 4. Referring more particularly to Figs. 5 and 6 showing details of construction and the valve gear of an intake valve, intake valve spring 46 is compressed between a wall of the cylinderblock and valve spring seat 80 which is slidably mounted upon a shouldered sleeve 81, the sleeve 81 being in turn guided upon valve stem 43 and held against downward movement thereon by a pin 82. An auxiliary valve spring 83 is mounted upon the valve stem 43 and is compressed between a boss on the cylinder block and washer 8 1 guided on valve stem 43 and bearing upon the sleeve 81.

Extending from the bracket 63 adjacent each of the intake valves is a pair of arms 85, upon which are pivoted at 86 forked arms 87 engaging the long rocker shaft 7 0. The forked arm 87 is adapted to be swung by the rocker shaft bet-ween its inoperative position shown in full lines in Fig. 5, and its operative position shown in dotted lines in this figure. Each forked arm 87 carries upon its pivot shaft 86 a cam 88 which is adapted to engage the spring seat 80 for the purpose of raising the same from the flanged sleeve 81, or for lowering the same into engagement with flanged sleeve 81. The arrangement of the parts is such that when the rocker shaft '70 is in its lower or inoperative position, as shown in full lines in Fig. 5, the spring seat will sufiice to open the intake valve.

80 bears upon the flanged sleeve 81', so that both the main spring 46 and. the auxiliary spring are activein holding the intake valve to its seat. But when therocker shaft 70 is moved to its operative position for engine cranking, as indicated in dotted lines in Fig. 5, the cams 88 serve to hold the spring seat 80 in elevated position, out of engagement with the flange of sleeve 81, so that now only the auxiliary and weaker spring 83 exerts pressure to hold the intake valve to its seat. It is apparent, therefore, that a lesser suction or expansion ofthe gaswithin the cylinder on the down stroke of the pis lt on he springs are so proportioned that a normal spring pressure is exerted upon the intake valve during engine operation, but during engine cranking the spring pressure is greatly reduced so as to permit the intake valve to open to admit gas and thus break the partial vacuum in the cylinder. The valve seat 80 may be lifted to any desired height during engine cranking, but it is found in practice that excellent results are attained with a lift of one-sixteenth inch, this allowing sufficient opening of the intake valve to break the partial vacuum within the cylinder at cranking speeds.

Mechanism for moving the rocker shafts between their operative and inoperative positions comprises a air of spaced brackets or arms 100 carried y the bracket or frame 63, between which arms there is pivoted at 101 a rock lever 102 which is forked at its lowerend to receive the rocker shafts 70 and as shown in Fig. 3. The upperend of rocker lever 102 is connected by means of a rod 103 or other suitableconnection with the arm 10 1 on control shaft 105, which control shaft preferably extends longitudinally of the motor vehicle and is mounted for rocking movement thereon. A spring 106 is connected between the rod 103 and a fixed part of the engine or of the motor vehicle for normally holding the auxiliary valve-control mechanism in inoperative position. As shown in Fig. 1 the fixed end of the spring 106 is connected to a projection or fin extending from the wall of the opening 107 formed in the cylinder block, in which openingthe rod 103 is located.

The auxiliary valve control mechanism is preferably controlled from aplurality of positions, for which positions the operator may be either on the motor vehicle or on the ground. Referring to ,Fig. 1 the control shaft 105 is provided with a handle 108 at its front end adjacent the hand crank 22, whereby the valve control mechanism may be readily rendered operative to reduce resistance to engine cranking when the cranking is done by hand at 22. Preferabl means is also associated with the starter utton 25 of the electrical starter whereby resistance to engine cranking may be reduced when cranking foot, thereby first rotating the control shaft 105 to bring the auxiliary valve operative mechanism intooperating position. Continned movement of the'pedal 112 causes the same to engage'and depress the starter button 25 thereby placing in operation the electrical cranking means. As soon as the engine becomes self-operative, the driver of the vehicle removes the tootpressure upon the pedal 112, thereby restoring the electrical starter and the auxiliary valve control mechanism. to their inoperative positions.

From the foregoing it will be apparent that the present invention provides a simple and inexpensive means for reducing the resistance to engine cranking which results -from the compressive and expansive movements of the pistons in their cylinders. During the up strokes of the piston, the exhaust valves are held open to relieve compression, and during the down strokes of the pistons, the intake valves are either opened or held to their seats under such reduced pressure as to offer but slight resistance to engine cranking as a re sult of expansion of the gases in the cylinders. The operation of the intake valves is such that a proper explosive fuel mixture is taken into each cylinder on .its intake stro e and such explosive mixture is still in the cylinder at the time of ignition during the firing stroke, although it will be observed that the fuel m xture is not under the usual compression owing to the fact that the compression valve was held open during the compression stroke. However, it has been found that the uncompressed fuel mixture burns or explodes readily and a single. explosion of such uncompressed fuel mixture liberates suiiicicnt power to put the engine in motion. Consequently the c 'anking may be discontinued after a tow explosions of the engine and, the auxiliary mechanism being thrown into its inoperative position, the engine will continue to operate in its normal manner.

An important advantage of the present invention is that the resistance to engine crankmaybe reduced to such an extent as to ren' der hand cranking unobjectionable in most instances. In fact the hand cranking means may be mounted in such a position that it may be operated from the drivers seat, thereby overcoming one of the great objections to hand cranking as now practiced, namely, the necessity for getting out of the motor vehicle to operate the hand crank. Even when an electrical starter isused to crank the engine, the present invention constitutes a valuable adjunct in that it eil ects a great saving in current during engine cranking and avoids early depletion of the battery. The advantage in the saving of current is so marked that in some cases the present invention enables the use of a smaller battery and hence effects a saving in the cost of the electrical equipment.

a result of the greatly reduced resist ance to engine cranking, it is feasible to so construct a dynamo electric machine 27 that it may be operable both as a cranking motor and as a generator without the introduction of the variable driving gears which are present required in single unit starters owing to the fact that the power of the motor must be greatly multiplied in order to overcome the high cranking resistance. In single unit starters of the known types the gearing which is suitable for cranking the engine, is not suitable for driving the dynamo electric machine a generator after the engine becomes selfoperative, owing to the fact that the dynamo electric machine would be operated at too high a speed. Therefore, such single unit starters commonly have means for changing the gear connection between the engine crankshaft and the armature shaft of the dynamoelectric machine when the latter changes from a motor to a generator. As already suggested, the present invention permits the elimination of such gear changingmechanism which at best is complicated and expensive and which greatly complicates the electrical construction oi the dynamo-electric machine. Oljwiously the present invention enables the practice of important economies in the cost of the electrical starting and generating system, and also enables the simplification thereof.

From the construction as disclosed in the drawing, it is apparent that the present invention may be readily applied as an a ccessory to self-contained engines.

lVhile the form of apparatus herein described constitutcs ttPlfiGfQl'l'Qtl en'ibodiment or the invention, it is to be understood that theinvention is not limited to this precise form of apparatus, and that changes may be made therein without departin from the scope of the invention which is derined in the appended claims.

hat is claimed is p 1. In a multiple cylinder engine comprising intake and exhaust valves iior each of the cylinders, valve gear for operating each 01": said valves, said valves being operated in a predetermined sequence to produce continuous operation of the engine, and auxiliary means for operating one of said valves from the valve gear of another valve during engine starting.

2. In a multiple cylinder engine comprising intake and exhaust valves for the cylinders, valve'gear for operating each of said valves, said valves being operated in a predetermined sequence to produce continuous'operation of the engine, and auxiliary means for operating one of said exhaust valves from the valve gear of another exhaust valve.

3. In a multiple cylinder engine comprising intake and exhaust valves for the cylinders, valve gear fo r'operating each ofsaid valves, said valves being operated in a predetermined sequence to produce continuous operation of the engine and auxiliary means for operating one of said exhaust valves from the valve gear of another exhaust valve, and means for rendering said auxiliary 'means operative or inoperative.

4. In a multiple cylinder engine comprising intake and exhaustvalves for each of the cylinders, valve gear for operatingeach of said valves, said valves being operated in a predetermined sequence to produce continuous operation of the engine, and auxiliary means adapted to be connected with the valve gear of the exhaust valves of two of said cylinders whereby valve-opening movement of either ofsaid valve-gears causes simultaneous opening of the exhaust valve of said other cylinder.

5. An internal combustion engine comprising a plurality of valves, valve gear for operating each of said valves, said valves be1ng operated in a predetermined sequence to cause continuous operation of the engine, and auxiliary means for operating one of said valves out of its normal order from the valve gear of another valve.

6. A four-stroke-cycle engine,,compr1s1ng intake and exhaust valves, yielding-pressure means for normally holding said intake valve closed during normal operation of the engine, and means for reducing without overcoming said pressure mgeans during engine starting, so that the valve may be seated during engine starting. 7

7; A four-stroke-cycle engine, comprising intake and exhaust valves, yielding-pressure means for holding said intake valve to its seat during normal operation of the engine, a second yielding-pressure means for holding said valve to its seat and means for rendering one of said yielding-pressure means inoperative.

8. A four-stroke-cycle engine comprising a cylinder having intake and exhaust valves, yieldingpressure means normally operable to hold said intake valve to its seat during engine operation, auxiliary yielding-pressure means also adapted to hold said intake valve to its seat, said auxiliary yielding-pressure means exerting a lower pressure on the intake valve than thefirst-mentioned pressure means, and means for rendering said firstmentione'd yie'ldingpressure means lnoperative during engine starting whereby to reduce the pressure on said intake valve during en- I named means.

10. An internal combustion engine of the four-'stroke-cycle type comprising a cylinder, intake and exhaust valves for said cylinder, yielding pressure means for holding said valves to their seats, a piston operable in said cylinder, said piston moving upwardly in the cylinder during the compression and the exhaust strokes, and moving downwardly in the cylinder during the suction and the explosion strokes, means for cranking the en gine, and means operable during engine cranking for opening the exhaust valve during the up strokes of the piston and for reducing the yielding pressure upon the intake valve during thedown'strokes of the piston, whereby to reduce resistance to cranking during the engine-cranking operation.

11. An internal combustion engine of the four-stroke-cycle type comprising a cylinder, intake and exhaust valves for said cylinder,

yielding-pressure means for holding said valves to their seats, a piston operable in said cylinder, said piston moving upwardly in the cylinder during the compression and the exhaust strokes, and moving downwardly in the cylinder during the suction and the explosion strokes, means for cranking the engine, and means automatically operable upon initiation of the engine-cranking operation, foropening the exhaust valve during the up strokes of? the piston and for reducing the yielding pressure upon the intake valve during the down strokes of the piston, whereby to reduce resistance to cranking during the enginecranking operation.

12. An internal combustion engine of the four-stroke-cycle type comprising a cylinder,

intake and exhaust valves for said cylinder,

yielding-pressure means for. holding said valves to their seats, a piston operable in said cylinder, said piston moving upwardly in the cylinder during the compression and the exhaust strokes, and moving downwardly in the cylinder during the suction and the explosion strokes, means for cranking the engine, and means automatically operable upon initiation of the engine-cranking operation, for holding the exhaust valve open during the up strokes of the piston and for reducing the yielding pressure upon the intake valve dur-' ing the down strokes of the piston, whereby V intake and exhaust valves for said oyllnder,

yielding-pressure means for holding said valves to their seats, a piston operable in said cylinder, said piston moving upwardly in the cylinder during the compression'and the exhaust strokes, and moving downwardly in the cylinder during the suction and the explosion strokes, means for cranking the engine, and a single member operable from a plurality of positions during engine cranking for opening the exhaust valve during the up strokes of the piston'and for reducing the yielding pressure upon the intake valve during the down strokes of the piston, whereby to reduce resistance to cranking during the engine-cranking operation. 7

14. In a motor vehicle, an internal combustion engine of the four-strokecycle type mounted on said motor vehicle, comprising a cylinder, intake and exhaust valves for said cylinder, yielding-pressure means tor hold 7 ing said valves to their seats, a piston operable in said cylinder, said piston moving upwardly in the cylinder during the compression and the exhaust strokes, and movmg downwardly in the cylinder during the suction and the explosion strokes, means operable'from the drivers seat of the motor vehicle for cranking the engine, a second means ior cranking the engine, means operable during engine cranking for holding the exhaust valve open during the up strokes of the piston and for reducing the yielding pressure upon the intake valve during the down strokes of the piston, whereby to reduce resistance during the engine-cranking operation, and

whereby to automatically cause operation of said last-mentioned means durin operation of said starting means.

15. An attachment for a self-contained engine of the four-stroke-cyole type having a cylinder, intake and exhaust valves for said cylinder-,a crank-shaft, valve gear operable from said crank-shaft for controlling said valves, and means for cranking the engine,

saidattachment comprising means operable during engine cranking for opening the exhaust valve during the engine compression stroke, means for reducing the normal pressure of the intake valve upon its seat during the explosion stroke, whereby to reduce the resistance to engine cranking, and means for detachably fastening said attachment to a side of the engine.

16. In a four-stroke-cycle internal combustion engine having valves operating as normal inlctand exhaust valves during normal engine operation, means operative during engine starting for causing the exhaust valve to open and close during the exhaust and the normal compressionstrokes, and means for automatically causing the intake valve to open and to close during the normal power stroke if the engine does not fire while still causing the normal opening and closing of the intake valve during the suction stroke.

17. In a i'our stroke-cycle internal combustion engine having inlet and exhaust valves therefor, means for automatically causing the intake valve to open and to close during the normal power stroke it the engine does not fire, said means having further provisions for causing the normal opening and closing of the intake valve during the suction stroke.

In testimony whereof I hereto affix my signature.

ROBERT A. FORBES. 

